The reel of a harvesting machine generally includes several support bodies that are radially distanced to and circumferentially distributed around a central tube. The support bodies can be formed as tubes or in any other profile. The support bodies are rotatably supported by corresponding support arms that are connected to the central tube. The reel is rotatable around the axis of the central tube. Commonly, at least 40 tines are attached on a reel for each support body to provide a working width of 6 meters. The design of the tine depends on the application of the harvesting machine. Tines made from spring steel wire are known. These tines are preferentially used with harvesting goods that are difficult to grip and to pull into the cutting trough, for example, cereals or grass, especially when they, because of the harvesting situation, rest on the ground. The tines generally have two or more spring windings between their attachment portion, with which they are attached on the support body, and the rod like gripping area. The tines contact the harvesting goods, via the windings, so that the gripping area can get out off the way, when it is heavily loaded.
For other harvesting goods, especially leguminous plants, for example beans, tines made from a plastic material are preferably used. These harvesting goods have to be cut very close to the ground, to collect all the fruit. Here, very wide cutting tables are used on the harvesting machines, for example, a combine harvester, that has a flexible cutter bar. The cutter bar is guided with ground contact in front of the cutting table. When the ground is uneven, these flexible cutter bars carry out a vertical movement relative to the cutting table. Thus, the cutter bar is lifted off the ground and approaches the tine moving above the same. In this case interferences are produced so that the tines can get between the reciprocatingly moving knife blades. If tines made from steel are used, the blades rip off. In this case the cutter bar can break and the cutter drive can be overloaded. The resulting repair times are undesirable during the harvesting work which depends on the weather.
Further, the loss of time has a larger effect than the cost for the repair. Because of this reason, tines are used in flexible cutter bars or for such application conditions that consist of an elastic material, for example, a nylon material, so that when such a tine gets into the cutting area of the knife, the tine is cut or shortened, respectively, by the knife blades. In this case, no damage is produced on the mower knife or on the knife drive. Such a tine can, for example, be exchanged during schedule maintenance.
Several embodiments of reel tines that are made from a plastic material are described in EP 0 475 405 A2. The tine is formed with a slotted eye-let for attachment onto the support body. The slotted eye-let is elastically expanded so that the tine, with its attachment area, can spring back after being pushed on. In this condition, attachment of the tine can be achieved by attachment bolts, or if necessary, additionally in connection with clamps and pins, to achieve locking, as via the support body a torque is introduced into the tine. The danger exists that, when harvesting goods accumulate on or when the tine hits a rigid object, an overload is produced. Different from a tine made from spring steel wire, a tine made from a plastic material has to be sufficiently elastic. During larger loadings, excessive bending and a non-regular circumferential position relative to the support body may be produced. This can lead, in the final effect, to breaking of the tine.
Tines are, however, also used in agricultural implements other than harvesting machines and reels, for example, in hay turning machines.
DE 177 83 79 U1 discloses, for example, a spring tine for a grass tedder, that is attached to a support body, for example an arm. The tine is bent from an integral steel rod. It has a rod-like gripping portion that contacts the grass. Furthermore, it has an attachment portion, bent into an eye-let, that attaches it, by means of a screw, onto the support body. A spring portion, an extending coil, is provided between the gripping portion and the attachment portion. In the opening, formed by the coil-like path of the spring portion, a sleeve, also mounted on the support body, engages the spring. Therefore, the tine is secured on the support body in a double manner. The rod-like gripping portion can avoid an obstacle in a pivoting manner around the spring axes determined by the retainment of the spring portion.
DE 178 20 043 U1 describes a tine for a spreading device, a tedder or rake, respectively. The rod-like tine includes a plastic material. Depending on the strength requirements, the rod-like tine can have reinforcement inserts. The required bending properties can, however, also be achieved by a corresponding design of the cross-sections. The tine is retained by screws on a carrying strap or similar support body.